Electric selection controlling circuit



Aug. 1, 1944. G. DEAKIN Erm.

ELECTRIC SELECTION CONTROLLING CIRCUIT Filed May s, 194s 2 sheets-sheet 1 .Ear T .I 1 of mn ew u. o .Nn QN m. mm .F @EBT A ,l on Q o om m. o o. m m m n N .r MOu- Uh` n l l l I l l l I I lllnvrulllllllllllllllwll IIIOIOI Tn llllllllll ||0 r l l I l I l I I I l I l I I IO ,If A I l I I l t l l I I l l l l l l I l l l q mu.

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' ATTORNEY Aug. 1, 1944, G. pEAKlN Em. 2,354,667

ELECTRIC SELECTION GONTROLLING CIRCUIT Y ATTORNEY Patented Aug. 1, 1944 Gerald Deakin, New York, N. Y., and Henry F.

Herbig, Madison, N. J., assignors to International Standard Electric Corporation, 'New York, N. Y., acci-poration o! Delaware Application May s, 1943, serial No. 4s5,szs

1s claims..v (ci. 17a-1s) This invention relates. to new and useful improvements in selection control circuits and more particularly to circuits for controlling the numerical selecting operation of selector switches employed in automatic telephone exchange systems.

The present is an improvement on the control I. circuits disclosed in the co-pending application of Gerald Deakin Serial No. 484,184, Ifiled April 23,

1943, and in the various applications and patentsY referred to therein.

The invention will be explained with reference to Figs. l to of the drawings which diagrammatically illustrate ve modications of as much of a control circuit, embodying the various features of the present invention, as is necessary for a clear understanding thereof.

In an automatic telephone system calllngfand called subscribers stations l and 2 may b`e interconnected by means including a plurality of selector switches 3 and 4. The numerical operations of the selectors are controlled by the calling .subscriber's customary impulse sender or other number indicating device through. the agency of a register provided at the central exchange. The

calling station l is connected to the brushes of selector 3 by non-numerical switches and a connecting circuit 6, and the register is attached to the connecting circuit 6 through switching means 5.

The selector switches are of the customary type having a bank of terminals with which a set of brushes cooperates. In the drawings three brushes are shown for selector 3 although the selector may have a larger number of brushes. The-selector brushes are moved over the terminals while a' magnet P is energized and are stopped on a set of terminals'when this magnet becomes de-energized.

The register comprises a series of switches successively operable by the calling device in accordance with the successive digits of the called number. A brush and a set of terminals of onejoi these register switches is shown in Fig. 1. This is the register switch which responds to the digit destined for selector 3. When brush RB is advanced towards one of the terminals I to Ill, in accordance with the operation of the calling device a t the station l, the register starting relay RSR, having been energized in the customary manner, a circuit is closed from ground over the armature and back contact of relay AR in the se- Y lector 3, the contacts of preceding selectors, the armature and front contact of relay- RSR in the register, the winding of a relay QR,y brush RB, the

negative grounded battery of the voltage indicated below these terminals. QR operates and closes an energizing circuit for relay AR and the -selector magnet P in parallel.

The magnet P starts the brushes of the selector to move over the terminals. Upon its energization relay AR removes the groundfrom the circuit of QR. However, once this relay pulls up it remains energized over resistance R1 to ground,

although it cannot become energizedwhen RSR iirst closes its circuit to ground over R1. Thus QR cannot release while the brush Ttravels from one terminal to the next. f

Preferably, the relay QR has a core which is fully saturated when connected in a circuit having a minimum potential difference, e. g. between six volts and ground. When the relay core is not fully saturatedin such circuit then its releasing time will vary after greater magnetization. The

core may be of any suitable material requiring a minimum of magnetizing flux. y

In this connection it should be noted that brush RB remains in contact with aA terminal when `it first touches the next terminal, but brush T cannot bridge adjacent terminals.

The rst terminal engaged by the-brush 'I' of y selector 3 is connected over a resistancerlto a six' volt tapv of negative battery. If the brush RB is resting on the rst terminal which is also con- 'nected to six volt negative battery, or ifl brush RB rests on another terminal, then when the selector brush T reaches vthe terminal to which the same.

potential is connected as the potential connected terminal engaged by the brush and positive or to the register switch terminal, then no current or insuilicientV current will flow through thwindlng.

of relay QR to maintain it energized and this relay will become de-energized. It will'openthe circuits of relay AR and magnet P whereupon the selector is stopped and the relay ARf makes the multiples of the terminal of which selectorbrush T rests busy .by applying 'ground thereto over its armature and back contact in the usual way.

The D. C. voltage applied to adjacent terminals of the register and selector switches may diiler by six or eight volts. The' iirst five terminals are connected to negative and the .second ve to positive poles of the battery.

As shown in Fig.y 1, the relay QR controlsdirectly in its front contact the circuits of relay AR and magnet P and thus breaks considerable current upon its de-energization. In order to avoid this, the arrangement shown in Fig. 2 may be adopted. When the relay QR energizes, it closes a shunt circuit from ground over its armature and front contact, the back contact and'left-handarmature and the winding of a second relay QRi and the iront contact and armature oi' a relay RSR: which at this time is energized in the register. While this condition prevails. the relay QR; cannot become energized and the selectorrelay AR and magnet P are maintained energized by ground over the iront contact of RSR: and the right armature' and back contact of QRi. The relay QR is con-- nected to the register and selector brushes in the samey manner as shown in Fig. l.

When the selector and register brushes engage terminals connected to the same potential. then the relay QR becomes energized, removes the shunt i'rom the winding oi QRi and permits this relay to energize over resistance Rz.l QRi opens the circuit oi AR and P whereupon the selector is stopped. QR1 immediately becomes de-energized, but in the meantime RSR: became de-enersized.

In the arrangements shown in Figs. 1 and 2, the polarity of the current ilowing through relay QR reverses as the selector brush T and the register brush RB move from one terminal to the next. In order to guard against a tendency for relay QR' to iall oil! during these reversals, it may be placed in a rectier bridge as shown in Fig. 3. Rectiilers S1 and Sn which are provided in the arms of this bridge are sopoled that the current ilow 4through the winding of QR will always be in the saine direction.

and the register brushes engage contacts and terminals, respectively, to which the same potentials are applied, and an operating circuit for the magnet controlled by said relay.

2. In combination, a numerical selector switch having a terminal bank containing sets of terf-lininals and a set ci brushes adapted successively Although some cross-talk may exist on account of the appreciable current which ilows over the wire connected to brush T when this brush passes over the terminals at high speeds, e. g., 100 terv als per second, the circuits shown in Figs.

1-'3 have the merit o! their simplicity and the absence of vacuum tubes or a high tension battery, and are thus particularly suited -ior P. B. X and similar installations. In the arrangement shown in Fig. 4. when the register brush RB is set von a terminal then relay DR operates over one winding to ground. Upon the energization of RSR, the selector is operated in the usual way. When the selector brush T reaches the terminal to which battery of the same potential is connected as to the register ,terminal, then the relay DR falls away because its two windings are differentially disposed and so designed that under this condition, and only under this condition, equal and opposite magnetizing forces will be developed. The selector will thus be stopped.

As shown in Fig. 5, the right-#hand winding of relay DR which is connected with the selector brush T isplaced in a rectiiler bridge so as to keep the iiow of current through'it always in the same directionv for the reasons pointed out in connection with Fig. 3.

What is claimed is: 1. In combination, a selector switch having two I sets of cooperating contacts, a magnet for oper- `ating saidv contacts, a register comprising a switch having a plurality of terminals and a brush adapted successively to engage them, means for operating the brush to engageany terminal, a relay in said register, a control circuit extending from the brush of the register to the rst set of contacts ofthe selector and vincluding the relay, a sourceoi potential, connections ior applying the same potentials to the terminals and to the second sets of selector contacts, there being a predetermined diii'erence between potentials applied to adjacent terminals and adjacent contacts, said relay being arranged to respond only when the ilrst set ot selector contacts to engage said terminals, a magnet for operating said brushes, a register comprising a switch having a plurality of terminals and a brush adapted successively to engage them, means for variably operating the brush of the register switch, a relay in said register, a control circuit extending from the register switch brush to a brush oi.' the selector and including said relay, a source of potential, connections for applying the same potentials to the register and selector terminals, there being a predetermined difference between potentials applied to adjacent terminals, said relay being arranged to respond only when the selector and register brushes engage terminals to which the same potentials are applied, and an operating circuit for the magnet controlled by said relay.

3. In combination, a numerical selector switch having a terminal bank containing sets of ter- .minals and a set of brushes adapted successively comprising a switch having a plurality of termi nais and a brush adapted successively to engage them, means for variably operating the brush of the register switch, a relay in said register, a con'- trol circuit extending from the register switch brush to a brush of the selector and including the register relay, a. source of potential, connections for applying the same potentials to the register and selector terminals, there being a predetermined diiierence .between potentials applied to adjacent terminals, said register relay being arranged to respond only when the selector and register brushes engage terminals to which the same potentials are applied, operating circuits for the selector relay and magnet controlled by said register relay, and a path', for applying a predetermined potential to the control circuit controlled by the selector relay.

4. The system according to claim 3, and in which a second relay is provided in said register, the circuit for the selector relay including a contact of the second relay, a third relay in the register for controlling the energizing circuit of said second relay, and a short circuit for the second relay controlled by the iirst register relay.

5. In combination, a plurality of numerically designated lines, a numerical selector switch having a terminal bank containing sets of terminals and a set of brushes adapted successively to engage said terminals. a magnet for operating said brushes, a register comprising aswitch having asource of potential, connections for applying the same potentials to the register and selector terminals, there being a predetermined difference between potentials applied to adjacent terminals,

lsaid relay beingarranged to respond only when the selector and register brushes engage terminals to which the same potentials are applied,

and an operating circuit for the magnet controlled by said relay.

6. The system according to claim 5, and in which said control circuit includes 'a rectifier bridge across the diagonals of which a winding of said relay is connected.

7. In combination,` a numerical selector switch having a terminal bankcontaining sets of terminals and a set of brushes adapted successively to engage said terminals, a magnet for operating said brushes, a, register comprising a switch having' a plurality of terminals and a brush adapted successively to engage them, means for variably operating the brush of the register switch, a relay in said register having two differential windings, a control circuit extending from the 'register switch brush to a. brush of the selector and including the relay, a source of potential, connec-4 tions for applying the same potentials to the register and selector terminals, ythere being a pre--A determined difference between potentials applied to adjacent terminals, said relay windings being arranged to respond only when the selector and register brushes engage terminals to which the same potentials are applied, and an operatingcircuit for the selector relay and magnet controlled by said relay.

8. The system according to claim 7,. and in which said control circuit includes a rectifier -bridge across which one winding of said relay is connected. l

9. In combination, a numerical selector switch having a terminal bank containing sets, of terminals and a set of brushes adapted successively toengage said terminals, a magnet for operating said brushes, a. relay in said selector, a register comprising a switch having a plurality of terminals and a brush adapted successively to engage the terminals, means for variably operating the brush of the register switch, a first relay in said register having a core whichis fully saturated when connected in a control circuit having a predetermined minimum potential difference,

a second relay in said register having a contact connecting the winding of said first relay in a control circuit extending from the register switch brush to a brush of the selector, ground connected to said control circuit over a resistanceof suchl value that the first relay, if energized, remains energized, sources of negative and positive D. C. potential, connections applying to a first group of terminals of the register and selector switches positive potentials differing one from the next by a predetermined voltage, and for applying to an adjacent second group of terminals negative potentials differing from one another by said predetermined voltage, parallel energizing circuits for the magnet/and selector relay including a contact of the rst register relay, and a. path from the control circuit to ground over a contact of the selector relay.

10. The system according to claim 9, and in which said control circuit includes a rectifier bridge across which the winding of said ilrst relay is connected.

11. In combination, a numerical selector switch having a terminal bank containing sets of terminals and a set of brushes adapted successively to engage said terminals, a magnet for operating said brushes, a relay in said selector, a register comprising a switch'having a plurality of terminals and a brush adapted successively to enlgage the terminals, means for variably operating the brush of the register switch in accordance with a numerical digit, a iirst relay in said register having a core which is fully saturated when connected in a control circuit having -a predetermined minimum potential diiIerence, a second relay in said register having a contact 'connecting the winding of said first relay in a control circuit extending from the register switch brush to a brush of the selector, ground connected to said control circuit over a resistance of such value that the ilrst relay, if energized, remains energized, sources of negative and positive D. C,

potential, connections applying to a first group of terminals of the register and selector switches, positive potentials differing one from the next by a predetermined voltage, and for applying to an adjacent second group of terminals negative land a path from the control `circuit to ground over a contact of the selector relay.

.12. In combination, a numerical selector switch having a. termina1 bank containing sets of ter` minals and a set of brushes adapted successively to engage said terminals, a magnet for operating said brushes, a relay in said selector, a register comprising a switch having a plurality of ter- Y minals and a brush adapted successively to engage the terminals, means for variably operating the brush of the register switch in accordance with a numerical digit, a first relay in said register having two, diierential windings connected to ground and one to the selector brush and the other to the register brush, a second relay in said register having a contact connectingv a contact of said rst relay to the circuits of the selector relay and magnet, sources of negative and positive D. C. potential, connections applying t'o a first group of terminals of the register and selector switches, positive potentials diierin'g one from the next by a predetermined voltage, and for 

